Creating a filled array with a given length?
jussi.kalliokoski at gmail.com
Thu Dec 13 01:14:42 PST 2012
On Wed, Dec 12, 2012 at 6:08 PM, Rick Waldron <waldron.rick at gmail.com>wrote:
> On Wed, Dec 12, 2012 at 1:59 AM, Axel Rauschmayer <axel at rauschma.de>wrote:
>> I would still love to have something like that in ES6 (loosely similar to
>> String.prototype.repeat). Once you have that, you can e.g. use
>> Array.prototype.map to do more things.
>> Two possibilities:
>> - Array.repeat(undefined, 3) -> [ undefined, undefined, undefined ]
>> - [ undefined ].repeat(3) -> [ undefined, undefined, undefined ]
>> The same array could be created like this, but that seems too much work
>> for a relatively common operation.
>> 'x'.repeat(3).split('').map(=> undefined)
> Array Comprehensions!
> This is probably wrong, so treat it more like an idea and less like a
> matter of fact:
> [ undefined for x of new Array(3) ].map( v => ... );
> [ undefined for x of [0,0,0] ].map( v => ... );
This should work, too (at least it works in Firefox, if you use a normal
var powersOfTwo = [ ...Array(8) ].map( (v, i) => 1 << i )
> es-discuss mailing list
> es-discuss at mozilla.org
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the es-discuss